"In consultation with his doctors, John has been advised that he has an elevated risk for a stroke," his family says in a statement explaining the postponement. "He will have surgery this week to insert a stent which will remedy the issue."
The concert has been rescheduled for 8 p.m. Wednesday, September 18, with the same opener, I'm With Her.
"[John] looks forward to a full and speedy recovery," the Prine family notes.
Tickets for the July 28 show will still be valid. For those who can't make the new date, refunds will be available at the point of purchase.